A piezo actuator is specified, which is formed from a plurality of piezoelectric layers with electrode layers located between them. When an electrical voltage is applied to the electrode layers, the piezoelectric layers expand, resulting in a linear movement being produced. Piezo actuators such as these are used, for example, for operating an injection valve in a motor vehicle.
When the piezo actuator is operated, mechanical stresses can occur, resulting in cracks, in particular also on an external electrode. This can lead to failure of the piezo actuator.
The document EP 0844678 B1 specifies a piezo actuator which has a three-dimensionally structured, electrically conductive electrode which is connected to basic metallization via partial contact points.